This study primarily aimed to investigate the Communication Apprehension (CA) experienced by students at the Rajamangala University of Technology Lanna (RMUTL) Phitsanulok, Thailand in the context of their English as a Foreign Language (EFL) classes. A total of 281 students from three faculties--Business Administration and Liberal Arts (BALA), Engineering (ENG), and Science and Agricultural Technology (SAT)--participated as respondents. Using a set of questionnaires for data collection, a quantitative statistical analysis was employed to derive meaningful insights. The outcomes unveiled a prevalent high level of CA among students in EFL classrooms, with responding to a teacher in English emerging as the most pronounced source of apprehension. Conversations also ranked as a highly anxiety-inducing context among the students who participated in the survey. The study identified reinforcement and modeling as the predominant factors contributing to the emergence of CA, wherein students' anxiety about speaking in an EFL classroom stems from a perceived lack of proficiency in English. Furthermore, students tend to avoid speaking situations in EFL classrooms due to concerns about potential judgment by classmates in the event of language mistakes. Noteworthy findings indicated that students in lower university year levels exhibited heightened apprehension compared to their counterparts in higher years. This study also revealed that students in the Faculty of SAT who take fewer English courses or subjects tend to experience greater apprehension compared to students in the other two mentioned faculties. Additionally, it was found that there is a positive correlation between lower grades in English and heightened CA. Lastly, students exhibited increased anxiety when engaging in oral communication with native-speaker teachers as opposed to their Asian counterparts.